NASA's falling satellite wasn't always a hunk of junk

Sometime Sept. 23, the remains of NASA’s 12,000-pound, 35-foot long Upper Atmospheric Research Satellite (UARS) satellite is expected to fall to Earth … somewhere on the planet.

As re-entry nears, NASA has been able to get a better idea of when the satellite, which has been floating around out of commission for six years, would enter the atmosphere and what path it might take from there. But it’s still a rough estimate: On Sept. 22, NASA said only that it would not be over North America during re-entry, but promised more updates. Solar activity has a significant effect of the satellite’s path, the agency said.

UARS is expected to break up in the atmosphere, with most of its material burning up and only about a tenth of it — heavy pieces made of titanium, stainless steel and beryllium — reaching the Earth’s surface, although the biggest chunk will still be about 300 pounds. But officials say that chances of anyone being struck by debris are slim (officially, 3,200 to 1).

Nevertheless, a satellite the size of a freight car falling to Earth illustrates for some the growing problem of “space junk” orbiting the Earth, which has prompted scientists to consider everything from a “space fence” for tracking the debris to zapping it with lasers

But before UARS fell into that ignoble category, it produced some ground-breaking (space-shifting?) atmospheric research that’s worthy of note.

UARS, launched in 1991 from the space shuttle Discovery, was “the first multi-instrumented satellite to observe numerous chemical constituents of the atmosphere with a goal of better understanding atmospheric photochemistry and transport,” NASA says.

The satellite collected data used to study ozone photochemistry, particularly the loss of ozone over the Antarctic. It also was used, shortly after its launch, to study how atmospheric transport spread sulfuric acid aerosols around the globe from the eruption of Mt. Pinatubo in the Philippines.

A lot of other studies followed over the years, including infrared mapping of aerosols and Polar Stratospheric Clouds; the first global maps made from space of chlorofluorocarbons and their products; how water vapor is transported in the atmosphere; and studies of ultraviolet and visible light from the Sun. NASA lists 10 of UARS’s scientific achievements them here.

UARS was taken out of commission in 2005, and since then the once-honorable research tool has been nothing more than space junk, cluttering up orbital paths and causing consternation to space-faring nations. Even in space, apparently, it’s a what-have-you-done-for-me-lately universe.

Meanwhile, if you want to track the satellite’s path Fox News got the satellite-tracking website to develop a widget that follows UARS. But be forewarned: because of heavy Web traffic it was having trouble loading.

About the Author

Kevin McCaney is a former editor of Defense Systems and GCN.


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